The present invention relates to apparatus for precisely moving heavy loads and particularly relates to a combination jack and roller tool for lifting heavy machinery and precisely moving it in a horizontal direction, for example, to align machine components or separate machines.
When moving heavy loads, e.g., when installing and adjusting heavy machines or machine components, it is frequently necessary to very accurately align (within alignment specifications) one machine with another or a machine component with another component or machine. For example, in the installation of turbine-driven power generators, it is necessary to provide accurate coaxial or concentric alignment of the shafts of the turbine and generator, oftentimes within a tolerance of only a few thousandths of an inch. This has been difficult to achieve under ideal conditions and frequently such precision alignment is necessary in environments not conducive to effecting such alignment, for example, when the machines are initially installed in a new power generation plant.
Oftentimes, heavy machines of this type are sited on their foundation elements in rather rough or coarse alignment, for example, by the use of large boom cranes. High cost considerations, in many instances, preclude use of such cranes for final precise adjustment of the machines or their components relative to one another. Frequently, after initial alignment is provided by the lifting crane, final alignments are provided in the vertical direction by hydraulic jacks and calibrated pieces of shim stock which are positioned between the foundation and the load in order to obtain substantial coaxial alignment in the vertical direction within accepted tolerances.
To achieve lateral and angular adjustment of the machines or component parts relative to one another, stops for example, jacking posts, are provided on one side of the machine, and jacks are employed against the opposite side of the base of the machine. The jacks shift the machine or one end of the machine laterally until it butts the jacking posts, thus locating the machine in proper lateral alignment. This method, however, is a rather crude way of obtaining substantially precise lateral alignment. For example, the friction generated by the weight of the machine must be overcome in order to slide the machine horizontally. Additionally, using jacks and jacking posts to laterally move the machine not only results in difficult to control movements but potential deflection of the load itself. That is, the lateral jacking process may introduce torsion and other stresses in the machine, e.g., in the support frame of a generator or turbine. These residual torsional and other stresses later tend to distort and, hence, misalign the machines or their component parts once disposed in final position. Consequently, there has been a need for devices or tools enabling controlled and precise movement of heavy loads, for example, on the order 40,000 pounds or more, in a manner which would permit precise positioning of the load within tolerances, for example, of several thousandths of an inch.
According to the present invention, there is provided apparatus for precision movement of heavy loads wherein the apparatus is low in cost and maintenance, can be readily used by skilled craft labor, and generally permits horizontal movement of the heavy load into a precise position within tolerances of several thousandths of an inch. Particularly, there is provided a combination jack and roller tool including a base and an adjustment wedge slidable along the base. A counter wedge is disposed on top of the adjustment wedge and is movable vertically in response to horizontal movement of the adjustment wedge. The counter wedge supports a cover member which is movable vertically with the counter wedge. A plurality of rollers are disposed between the cover and the counter wedge whereby the cover is also movable horizontally relative to the counter wedge and the base. More specifically, the counter wedge has a recess along its upper surface for receiving a plurality of roller bars which extend transversely to the direction of relative movement of the cover member and the base. The roller bars are free and are carried by the counter wedge for rolling movement in response to relative movement of the cover member and counter wedge. The rollers, however, fill the recess and are therefore restrained from rolling movement by the end edges of the recess. One or more reduced diameter roller bars, forming part of the plurality of roller bars, are configured and oriented for removal from between the cover member and counter wedge when the load is supported on the apparatus, as described hereinafter, thereby to enable relative linear movement between the cover member and counter wedge and rolling movement of the bars.
Coarse adjusting screws cooperate between the base and the counter wedge to move the counter wedge along the adjustment wedge relative to the base to adjust the elevation of the cover member. That is, when the tool is disposed in the gap between the load and its foundation, the coarse adjusting screws are displaced to raise the cover member into engagement with the underside of the load. A power screw is carried for rotation by the base and is threaded to the adjustment wedge. Thus, when the power screw is rotated, its threaded engagement with the adjustment wedge causes the adjustment wedge to slide horizontally and, hence, causes the counter wedge, roller bars and cover member to lift the load. Horizontal adjustment screws cooperate between the cover member and the base to move the cover member and load carried thereby horizontally relative to the base. That is, when the apparatus is supporting the load and the reduced diameter end roller bar or bars are removed, the remaining roller bars roll freely within the confines of the recess in the counter wedge in response to relative movement of the counter wedge and cover member. By thus freeing the cover member for horizontal movement relative to the base, the horizontal adjusting screws are used to incrementally adjust the horizontal location of the load relative to the base and into the desired precise position.
In using the apparatus hereof, and in connection with a preferred embodiment thereof wherein, for example, a generator may be mounted in coaxial alignment (within specifications) with a turbine, the generator is first coarsely aligned with the turbine axis by a crane. Calibrated shims are used to adjust the axis of the generator relative to the turbine axis such that the axes are at like elevation within the prescribed tolerances. To provide for lateral alignment of the generator and turbine axes, the combination jack and roller tool hereof is placed under each of the four corners of the generator. By threading the coarse adjustment screws, the counter wedge slides along the adjustment wedge and elevates the cover member into engagement with the underside of the generator support frame. It will be appreciated that the roller bar axes are aligned generally parallel to the axes of the machines whereby movement of the cover member relative to the base, and hence the generator, is in a direction transverse to the axes to be aligned. The power screw of each combined jack and roller is then rotated such that the generator is supported thereby. The horizontal adjustment screws are then rotated to displace the cover member and, hence, the generator, transversely relative to the base the required incremental distance. It will be appreciated that the combined jack and roller tools at only one end of the generator may be used whereby the generator may be displaced angularly to align the axes. When the generator axis is precisely aligned with the turbine axis within the allowed tolerances, the power screw is rotated in the opposite direction to relieve the loading on the tool. The generator then settles onto the vertical adjustment shims and is fixed in the adjusted position in the conventional manner.
In a preferred embodiment according to the present invention, there is provided apparatus for controlled precision movement of heavy loads comprising a base, an adjustment wedge carried by the base for generally horizontal movement relative thereto and a counter wedge carried by the base in engagement with the adjustment wedge for generally vertical movement in a direction generally normal to such horizontal movement and in response to horizontal movement of the adjustment wedge. Also provided is a member adapted to carry the load and which member is carried by the counter wedge for vertical movement therewith and horizontal movement relative thereto. A first means for moving the adjustment wedge generally horizontally to move the counter wedge and the member generally vertically to lift the load and a second means for moving the member relative to the base for longitudinally moving the load are provided.
In a further preferred embodiment according to the present invention, there is provided apparatus for controlled precision movement of heavy loads comprising a base, an adjustment wedge carried by the base for generally horizontal movement relative thereto and a counter wedge carried by the base in engagement with the adjustment wedge for generally vertical movement in a direction generally normal to the horizontal movement and in response to horizontal movement of the adjustment wedge. Also provided is a cover member adapted to carry the load and which member is carried by the counter wedge for vertical movement therewith and horizontal movement relative thereto. First means are provided for moving the adjustment wedge generally horizontally to move the counter wedge and the member generally vertically to lift the load, and a plurality of roller bars cooperate between the member and the counter wedge enabling relative horizontal movement of the member and the counter wedge. Stops are spaced longitudinally one from the other in a direction transverse to the axes of the roller bars and, in one position thereof, preventing rolling translatory movement of the roller bars in the transverse direction and, in another position, enabling rolling translatory movement of the roller bars in the transverse direction and second means are provided for moving the member relative to the base for longitudinally moving the load.
Accordingly, it is a primary object of the present invention to provide a low-cost, low-maintenance combined jack and roller tool which is readily and easily used by skilled craft labor for effecting precise movement of heavy loads whereby, for example, accurate alignment of the movable load with other equipment and components may be easily achieved.
These and further objects and advantages of the present invention will become more apparent upon reference to the following specification, appended claims and drawings.